Tract-specific magnetization transfer ratio provides insights into the severity of degenerative cervical myelopathy.

Study design: Cross-sectional study.

Objectives: This study's goal is to report whether Magnetization Transfer Ratio (MTR) can evaluate the severity of white matter (WM) injury in degenerative cervical myelopathy (DCM).

Setting: Laureate Institute of Brain Research, USA; Department of Neurosurgery, University of Oklahoma Health Sciences Center, USA.

Methods: 27 DCM patients were aged-matched with 20 healthy controls (HC) and categorized into treatment groups based on modified Japanese Orthopedic Association (mJOA) severity (11 mild and 16 moderate/severe). Regional and tract MTRs were extracted from the two vertebral levels containing maximum compression within magnetization transfer images. MTR differences between groups were assessed using a one-way ANOVA or Kruskal-Wallis test. The association between MTR and mJOA measures was evaluated using Spearman's correlation.

Results: Significant decreases in MTR were found between HC and moderate/severe groups in the overall (p = 0.0065) and ventral (p = 0.0009) WM regions; and ventral corticospinal (p = 0.0101), ventral reticulospinal (p = 0.0084), spinal lemniscus (p = 0.0079), and fasciculus cuneatus (p = 0.0219) tracts. The spinal lemniscus MTR also significantly decreased between HC and mild groups (p = 0.038). Ventral reticulospinal tract MTR correlated with upper (r = 0.439; p = 0.022) and lower (r = 0.386; p = 0.047) limb motor mJOA scores.

Conclusions: Significant tract-based MTR changes and correlations align with known DCM symptoms, are demonstrated to be lost at the regional level, and display the inhomogeneous compressive damage occurring within DCM spinal cords.